Stabilized petroleum wax



s'rmznn PETROLEUM wax Everett W. Fuller and Bertrand W. Story, Woodbury,N. 3., assignors to Vacuum Oil Company,

Ina, New York, N. Y

' York a corporation of New No Drawing. Application February 25, 1932,

Serial No. 595,226

3 Claims.

This invention relates to the production of petroleum waxes, such asrefined paraflin wax, which are relatively resistant to oxidation by theatmosphere when maintained at temperatures above the melting point.

In the use of parafiin wax for the purpose of impregnating paper andother materials, it is customary to keep the wax at a temperaturesubstantially above its melting point, and in contact with theatmosphere. It has been found that ordinary wax, particularly whenhighly refined, deteriorates rapidly under these conditions, owing tooxidation and the formation of acidic bodies. We have found, however,that such oxidation may be so far prevented or retarded, by the additionto the wax of a small quantity of certain organic disulphides, as toprevent substantial deterioration under ordinary conditions of use.

In our application for Letters Patent of the United States filed June10, 1931, Serial No. 543,- 396, we have disclosed the fact that organicdisulphides in general have an oxidation inhibiting effect on highlyrefined petroleum oils, such as transformer oil and lubricating oil. Inthe case of the petroleum waxes, however, we have found that a similareflect is not produced, to a practically useful degree, by all of theorganic disulphides, but that it is a useful characteristic of thedialkyl disulphides. The present invention accordingly resides in theaddition, to a petroleum wax, of a relatively small amount, in theorderof .01% to 20% of the weight of the wax, of a dialkyl disulphide, forthe purpose and with the result of stabilizing the wax againstoxidation.

The efl'ect of the addition is shown by an accelerated test performedupon a refined petroleum wax melting at approximately 50 C. In this testeach sample was maintained at a temperature of 120 C. for ninety-sixhours, while oxygen gas was bubbled slowly through the melted wax. Theacid content was then determined in terms of milligrams of potassiumhydroxide required to neutralize one gram of the wax. In the case of thewax alone, the measure of acidity was 37.2 milligrams. The effects ofthe addition of various disulphides is shown in the following table,showing, in each case, the name and the amount of the disulphide and thecorresponding acidity:

1 .05% di-iso-amyl disulphide .05 .05% di-n-butyl disulphide .07 .05%di-n-propyl disulphide .07 .05% dibenzyl disulphide .03 .01% dibenzyldisulphide .00

Larger amounts of the disulphides may be used .with somewhat increasedeffectiveness, but they are unnecessary for most purposes, since theamounts stated reduce the acid formation to a practically negligiblequantity.

Where a high temperature is to be used the less volatile disulphides,such as dibenzyl disulphide, are preferable, and dibenzyl disulphide hasthe further advantage of being particularly effective in inhibitingoxidation.

The invention claimed is:

1. The combination, with a petroleum wax, of a relatively small amountof dibenzyl disulphide, as an inhibitor of oxidation.

2. The combination, with a petroleum wax, of a relatively small amountof an oxidation inhibitor comprising a dialkyl disulphide.

3. The combination, with a petroleum wax, of a relatively small amountof an oxidation inhibitor comprising one or more of the dialkyldisulphides:

di-iso-amyl disulphide, di-n-butyl disulphide, di-

n-propyl disulphide and dibenzyl disulphide.

EVERETT w. FULLER. BER'IRAND w. STORY.

